<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
	</body>
	<script type="text/javascript">
		"use strict"
		var obj={
			name:"snw"
		};
		Object.defineProperty(obj,"age",{
			value:18,
			writable:false,
			configurable:true,
			emumerable:true
		});
		obj.age=30;
		console.log(obj.age);
	</script>
</html>
